Electronic components such as electronic displays are commonly installed within flat, hard surfaces of electronic devices, such as computer screens, television sets, smart phones, tablet computers, etc., and in many cases are installed on accessories for the electronic devices, such as removable monitors. Many electronic devices having an electronic display are portable, and have thus become very useful in implementing mobile applications. This fact is particularly true with smart phones which have become ubiquitous. However, unfortunately, typical mobile devices such as smart phones have electronic displays that are flat and rigid in nature. Thus, while these displays are useful in implementing many different applications, the device on which the display is present must still typically be held in a hand, or must be stored in a pocket, a purse, a briefcase or other container, which makes the electronic device less accessible in many situations, such as when a person is carrying other items, undertaking an athletic activity such as running, walking, etc. Moreover, in many cases these traditional electronic devices require two free hands to hold and operate, making these devices cumbersome or difficult to use or to view in situations in which, for example, a person has only one or no free hands or is otherwise occupied.
While flexible displays are generally known and are starting to come into more common usage, flexible displays have not been widely incorporated into easily portable items such as items of clothing, wristbands, jewelry, etc., or on items that are easily attached to other items, much less in a manner that makes the display more useable and visible to the user in many different scenarios.
A flexible electronic component, such as a flexible electronic circuit, a sensor tag, a flexible OLED light, or a flexible display, is a multi-layered stack typically formed of both brittle and organic layers. In some cases, the flexible electronic component may include built-in strains that exist in one or more layers of the component due to the processing conditions of the component (e.g., temperature induced strain). In any case, as a flexible electronic component is typically produced on a flat surface, a curvature or bending of the flexible electronic component creates a certain strain profile in the layers of the component. The strain profile created by the curvature of bending of the component, as well as any built-in strains that may exist within the component, may, in turn, cause one or more of the layers of the flexible electronic component to buckle, crack, or otherwise become damaged. The organic layers in a flexible electronic component can typically withstand strains up to 8% before breaking or deforming in a non-elastic way. The brittle, inorganic layers in a flexible electronic component can, however, only typically withstand strains of approximately 1% before buckling or cracking, depending of course on the processing conditions of the component. As such, the brittle layers of the flexible electronic component generally buckle or crack first in response to excess strain.
When a flexible electronic component is bent or curved, the outer radius of the component will be under tension, while the inner radius will be under compression. At some point in the layer stack of the component, the neutral plane, where there is no tension or compression upon bending, can be found. The layer stacking, the layer thickness, and the layer properties, such as the Young's modulus, determine the position of the neutral plane; for a symmetrical stack of layers the neutral plane is generally located near a middle of the stack. Based on the exact location of the neutral plane and the maximum tolerable strain value (e.g., 1%), the minimum bending radius can be determined for each of the layers in the component. Because, as noted above, the brittle, inorganic layers in the component can typically withstand less strain than the organic layers, the brittle layers typically have a greater minimum bending radius than the organic layers. In turn, the greater minimum bending radius of these brittle layers governs or controls the amount of bending or curvature that the flexible electronic component can undergo before the component is damaged (i.e., the bending range of the component).
To provide support to the flexible electronic component and prevent a user of the flexible electronic component from bending or flexing the component beyond such a minimum bending radius, and, thus, prevent damage to the component, the component can be fixedly attached to a mechanical support structure. International Patent Application Publication No. WO 2006/085271, for example, describes attaching a metal leaf spring to a flexible display. As another example, U.S. Patent Application Publication No. 2013/0044215 describes a wearable article that includes a flexible display and a bi-stable snap metal strip attached to the flexible display.
The problem with attaching a flexible electronic display to a mechanical support structure, such as, for example, a metal leaf spring, is that the attachment of the mechanical support structure to the display typically causes the neutral plane to shift from its initial position (in the display) to a position within the mechanical support structure. Because of the relationship between the location of the neutral plane and the minimum bending radius, shifting the neutral plane in this way significantly increases the minimum bending radius of the layers in the display, particularly the brittle layers in the display. In doing so, the mechanical support structure can serve to significantly reduce, if not effectively destroy, the bending or flexing ability of the flexible electronic display. This is generally true for other flexible electronic components as well.
Moreover, these mechanical support structures, and other known mechanical support structures, do not sufficiently protect the flexible electronic component to which they are attached. Specifically, known mechanical support structures do not sufficiently limit bending of the flexible electronic component, or portions thereof, such that a user of the flexible electronic component can bend or flex the display beyond its minimum bending radius, bend or flex the flexible electronic component in more than one direction, and/or cause defects in the flexible electronic component, thereby damaging the component. The metal leaf spring described above, for example, may help fix the flexible display in the readable position, but does not actually prevent the flexible display, whether in this position or another position, from being bent or flexed beyond its minimum bending radius or from being bent or flexed in multiple directions. Meanwhile, the bi-stable snap metal strip noted above is not concerned with limiting bending of the attached wearable display product. When, for example, the bi-stable snap metal strip is in a flat state, the bi-stable snap metal strip provides little to no resistance against upward (counter-clockwise) bending, such that the wearable product, and, more particularly, the flexible display, can be freely bent in this direction. When the bi-stable snap metal strip is in a curled state, the bi-stable snap metal strip provides little to no resistance against further bending, such that the wearable product, and, more particularly, the flexible display, can be freely bent in this direction. When bending in either or both of these directions exceeds the governing minimum bending radius of the flexible display, the layers of the flexible electronic component can break, crack, or otherwise become damaged.